Rotary pump



Jan. 17, 1961 P. ALJ-no ROTARY PUMP Filed oct. :5, V1958 l/ Paul Hu fioINV EN TOR.

Unite This invention relates to rotary pumps, and more particularly topumps suitable for pumping a fluid mass containing abrasive or othersolid material entrained therein. Such fluids are exemplified byabrasive containing sludges, and certain solid-liquid mixtures whereinthe liquid of the mixtures is employed as a transferring medium for thesolids of the mixtures. Illustrative of the latter type of mixtures isthe ground and splintered bone, meat, and water mixtures which arepumped as feed for certain carnivorous animals. The pump of theinvention is characterized by a number of novel features whichcontribute to a long and trouble-free life for the pump, and running ofthe pump without its jamming or locking up.

Generally, it is an object of the invention to provide, in a rotary pumphaving a housing and impeller blades rotatable in the housing, mechanismfor moving the blades in their mounting radially in and out in such away that a stream or jet of the uid pumped by the pump is ejected pastthe outer end of each blade as the blade moves next to the usual outletport of the pump, whereby the blade extremity is cleaned of any sol dmatter which otherwise might tend to lodge on the blade end and causejamming and wear in the pump.

Another object is to provide a construction for moving such impellerblades radially to and fro which is positive in action and can take longand sustained use without appreciable wear.

In the art to which this pump relates, it is a known expedient to mountthe impeller blades of a pump eccentrically in a substantiallycylindrical pump chamber, so that the blades are moved about a rotationaxis which States Patent-O is offset radially from the center axis ofthe pump chamber. The blades are loosely mounted, and move to and froduring operation. As a result of the eccentricity of their mountingrelative to the cylindrical boundary wall of the pump chamber, adjacentpairs of blades and the boundary wall define a moving, liquid conliningchamber of diminishing cross-section progressing from the inlet to theoutlet port of the pump. Thus compression of the uid handled takesplace. This invention contemplates, in such a pump having eccentricallyarranged impeller blades and a mounting for the blades accommodatingshifting movement thereof relative to the impeller rotation axis, meanspositively actuating the blades producing a shifting movement whereinthe ends of the blades are kept snugly against the cylindrical boundarywall during most of their movement from the inlet to the outlet port forthe pump, and then moved away from the cylindrical pump chamber boundarywall slightly before coming into registry with the outlet port of thepump. The result is a construction wherein the liquid confining chamberdefined by an adjacent blades and the cylindrical wall is opened to theoutlet port prior to the time the leading blade which denes the chambermoves over the outlet port. As a consequence, a thin jet of uid isforced over the expanse of the leading blade, and a cleaning or washingaction takes place which functions to remove any matter lodged on theblade end.

Fice

A common feed employed in a mink farm comprises a mixture of water andcomminuted meat and bone material. This may be delivered to various feedstations using a pump. With conventional pumps, bone chipsV and othersolid matter collecting on the moving pump parts has caused jamming ofthe pump and frequent failures. The pump of this invention, by reason ofthe cleaning action discussed, has been used in suchapplications withquite satisfactory results.

The invention also features the use of a novel cam mechanism moving theblades to and fro on their eccentric mounting. Specifically, acamintegral withV the pump housing is provided which rides againstenlarged abutment shoulders carried by the impeller blade elements. Theabutment shoulders have enlarged bearing surfaces which engage thecam,.and these surfaces'are constructed so as to withstand long hours ofoperation without noticeable wear.

These and other 'objects and advantages are attained by the invention,which is described hereinbelow in conjunction with the accompanyingdrawings wherein:

Fig. 1 is a plan view of a rotary pump constructed according to anembodiment of this invention, with portions ofthe pump housing removedand illustrating various parts of the pump, and, in dotted outlines,various working positions of blade elements in the pump; and

Fig. 2 is a section View along the line 2-2 in Fig. 1, showing furtherdetails of the pump construction.

Referring now to the drawings, 10 indicates generally a pump housingcomprisinga substantially cylindrical boundary wall 12, and oppositelydisposed end wall portions 14 and 16. Walls 12, 14 and 16 delinetogether a substantially cylindrical pumpV chamber within the interiorof the pump housing. To enable assembly of the pump components, wall V16is shown as an end plate detachable from cylindrical boundary wall 12.Walls 12 and 14 are integral' with each other.

Wall or plate 16 has around the perimeter thereof an annular angeportion 18 which projects radially outwardly of wall 12. Slots 20, 21formed in diametrically opposite positions of flange portion 18 receivethe shanks of a pair of swivel screws 22, 23, which are pivotallymounted by pins 24 on sets of lugs 26 integral with cylindrical wall 12.Plate 16 is secured in place as in Fig. 2, by swinging screws 22, 23 toa vertical position with the shanks of the screws in slots 20, 21, andturning wing nuts 28 downwardly on the externally threaded ends of theswivel screws.

Rotatably mounted within the confines of the pump chamber is an impellermechanism or means indicated generally at 30. The impeller mechanism isrotatable about a rotation axis indicated at 32 (see Fig. 2), which isradially offset from the center axis of the cylindrical pump chamber.

Impeller mechanism 30 comprises a substantially cylindrical core ormounting hub portion 36, a circular plate portion 38 integral with hub36 and supporting the hub on wall 14, and a drive shaft portion 40integral with plate 38 which extends downwardly and outwardly throughthe end wall 14. End wall 14 is provided with a sleeve portion 42encircling shaft portion 40. The pump is actuated by a suitable motor(not shown) rotating shaft 40.

The outer surface or Wall of hub portion 36 lies at its closest to theinner surface of wall 12 along a line where the inner surface of Wall 12is closest to the rotation axis 32 of the impeller. The end o-f such aline is indicated in Fig. 1 at A. Proceeding in a counterclockwisedirection from this line in Fig. 1 (which, in operation -of the pump, isthe direction of rotation of the impeller means) the outer surface ofhub 36 diverges from the inner surface of wall 12 until a point ofmaximum separation between the two is reached, which is along a lineWhere the inner surface of wall 12 lies at its maxmium distance fromaxis 32. Th's l'ne is indica'ed at B in Fig. l and is along adametrically opposite side of wall 12. Continuing from line B, the Wallsof hub 36 and wall 12 converge until line A is reached.

An inlet port is provided which cmrnunz'cates with the pump chamber atan area where the hub wall and wall 12 are diverging. An outlet port isprov'ded wh'ch communicates with the pump chamber at an area where thehub wall and wall 12 are converging. The outlet port is angularly spacedabout the rotation axis of the impeller means from the inlet port.Flufd, in moving from the inlet to the outlet port, is subjected tocompression, as the fluid is transported between the two ports through aliquid confining chamber of diminishing crosssection.

More specifically, loosely mounted on hub 36 for movement to and froradially of the impeller rotation axis are a pair of crossed impellerblade elements 50, 51. These are arranged at right angles to each other,so that the ends of the blade elements are spaced at regular angularmodules about axis 32. The blade elements have a length slightly lessthan the leng h of the shortest chord subtended by curved wall 12 whichpasses through axis 32. Blade element 50 occup'es the position of such achord, and it may be seen, with reference to Fig. l, that the length ofelement 50 is such as to allow slight radial play of the element when inthe position shown.

Blade elements S0, 51 are mounted for reciprocation in slots 56, 57, 58and 59 formed in the walls of hub 36. These slots extend from the top ofhub 36 downwardly to the plane of the top of plate portion 38. Bladeelement 50 has outer end portions joined by a web portion 61 spacedclosely to the base of the hub, whereas blade element 51 has outer endportions joined by a web portion 62 spaced upwardly from the base of hub36 and overlying web portion 61.

The blade elements have cutouts 66, 67 indented into their top edges.Cutout 67 of blade element 50 receives web portion 62 of blade element51. The cutouts perform a further function. Thus, upstanding edges 71,72, 73 and 74 dening the side limits of the cutouts are expanded, andhave a T-shaped cross section. These edges constitute abutment shouldersin the device. The radially inwardly facing outer surfaces of theseedges are convexly curved, and provide enlarged bearing surfaces ofsubstantially greater width than the thickness of a blade element.

Integral with detachable end wall 16, and projecting downwardlytherefrom, is a kidney shaped noncircular cam 76. The cam fits withinthe hollow interior of hub 36 with the peripheral cam surface thereofcontacting the abutment shoulders of the blade elements. Since the camis in fixed position, and the impeller means is rotatable in thehousing, movement of the irrpeller means causes the blade element to beshifted back and forth by cam 76.

The positioning of the cam relative to axis 32 is critical. Referring toFig. l, it will be noted that the cam is positioned so that on movementof the imp-ller, the end of a blade element first is shifted outwardlyagainst the inner surface of wall 12, progressing from a point C in Fig.1 in a counterclockwise direction. The blade element end positively isforced against the inner surface of wall 12 until the blade element endreaches a point D. At this point the blade element end is shiftedradially inwardly, over about a ten degree arc, with the opposite end ofthe blade element moving against the inner surface of wall 12. Thus thecam 76 has a cam surface engaging the abutment shoulders to positionblade elements that includes a curved portion 76a that curves in a sweepcoinciding with the locus described by the abutment shoulders with theblade portions snugly against said boundary wall and immedately prior toand during their initial movement from the inlet to the outlet ports.This causes the blade elements to pass snugly adjacent boundary wall 12during their initial movement. The cam surface of cam 76 then has areceding portion 76b that recedes inwardly from such a locus duringfinal movement of the blade portions between the inlet and outlet portsand when the blade elements approach the outlet port. This accommodatesradially inward movement of the blade elements during this finalmovement.

Extending axially into the pump chamber and communicating with thechamber at a location spaced next to the path of movement of the sidesof the blades elements is an inlet port 91. Port 91 has an elongated,substantially arcuate shape, conforming generally to the shape of thespace between the wall of hub 36 and wall 12. Extending radially of thepump chamber and communicating with the chamber at a location spacednext to the path of movement of the ends of the blade elements is anoutlet port 92. It will be noted that the inlet port lextends over toand ends at the area of maximum separation between the wall of hub 36and wall 12. It will also be noted that the outlet port communicaes withthe pump chamber at an area where the wall of hub 36 and wall 12 areconverging.

The outlet port is angularly spaced about the rotation axis of theimpeller means from the end of the inlet port an angular distanceslightly in excess of degrees (about degrees). Thus two successive bladeelement ends, when in the position of ends 50a and 51a illustrated inFig. 1, define with the wall of the hub 36 and wall 12 a liquid conningchamber which is closed off at both of its ends.

In operation, fluid flows into the pump chamber through the inlet portand collects in the space bounded on each end by a blade element end. Onrotation of the impeller mechanism, liquid caught between successiveblade ends is moved in the pump chamber until the blade ends occupyabout the position of ends 50a, 51a. At this point, liquid carriedbetween the ends of the blade elements tends to be compressed (due tothe convergence of the wall of hub 36 and wall 12).

On continued movement of the impeller, the blade element end occupyingthe position of end 5`a starts to move radially inwardly. This opens upa small space between the end of the blade element and wall 12, and thisopening of the space occurs before the end moves over port 92. As aresult, a jet of liquid is forced over the end of the blade element,which clears away foreign matter such as chips 7S from the end of theblade element. Continued movement of the impeller places the leadingblade element in full registry with the outlet port, and fiuid isdischarged through the port.

With a blade element end in the position of blade end Slb in Fig. l, anysolid caught between the outer surface of hub 36 and the inner surfaceof wall 12 can escape into the slot formed in hub 36 which slidablymounts the blade portion. On further rotation of the impeller, thismaterial is ejected from the slot by move- Vment of the blade endradially outwardly from the hub.

By using an axia'ly extending inlet port, the ends of the blade elementsare prevented from catching up large amounts of solid matter at theinfeed end of the pump. On the other hand, a radially extending outletport is provided, in order that discharge of fluid take place over vtheends of the blade elements.

While a blade end moves away from Wall 12 before reaching the outletport, it does not do so until the following blade end has closed off theinlet port. Thus the inlet and outlet ports are never open directly toeach other, and the pump is a positive displacement pump.

I claim:

1. ln a rotary pump, a housing having a substantially cylindricalboundary wall and oppositely disposed end walls dening the side andradially outer limits of a cy lindrical pump chamber, a mounting hubrotatably mounted within said pump chamber for rotation about a rotationaxis parallel to and offset radially from the center axis of said pumpchamber, said hub having a cylindrical hub wall concentric with saidrotation axis and defining the radially inner limits of said pumpchamber, said hub Wall along one side thereof being positioned snuglyadjacent one side of said cylindrical boundary wall, means defininginlet and outlet ports communicating with said pump chamber at locationsdisposed on each side of where the hub and boundary walls are snuglyadjacent, said ports being connected within the housing by a convergingportion of the pump chamber that is defined by converging hub andboundary walls, said hub during operation of the pump rotating in adirection wherein the wall of the hub moves from said inlet to saidoutlet port in said converging portion of the pump chamber, pluralcrossed impeller blade elements mounted on said hub with opposite endportions extending radially outwardly from said rotation axis androtatable with said hub, said hub being provided with slot meansaccommodating radial shifting of the blade elements on the hub, the endportions of said blade elements being regularly angularly spaced on thehub and the spacing between successive end portions being less than theangular spacing of the inlet and outlet ports in said converging portionof the pump chamber, and means positively for shifting the bladeelements radially to and fro, said means comprising opposed and radiallyinwardly facing abutment shoulders integral with each blade element7 and`a stationary noncircular cam element occupying a plane extendingtransversely of said rotation axis and projecting between the abutmentshoulders of each blade element, said cam element having a curvedsurface constructed to bear against an abutment shoulder of a bladeelement so as to force an end portion thereof snugly adjacent saidboundary Wall throughout all but final movement of the end portion fromsaid inlet to said outlet port and during final movement to bear againstan abutment shoulder so as to shift the end portion away from saidboundary wall, said final movement starting at substantially the timethe next following end portion starts beyond said inlet port, suchmovement of the blade elements in the converging portion of the pumpchamber resulting in a flow of uid over the end portions of the bladeelements during their such iinal movement.

2. The pump of claim 1 wherein said outlet port com- Y municates withsaid pump chamber through said cylindrical boundary wall.

References Cited in the tile of this patent UNITED STATES PATENTS 19,581Peirce Mar. 9, 1858 115,254 Tenant May 23, 1871 333,356 Taber Dec. 29,1885 629,796 Lobee Aug. 1, 1899 1,407,620 Ambrose Feb. 21, 19221,922,951 Hawley Aug. 15, 1933 FOREIGN PATENTS 70,672 Switzerland of1915 74,754 Austria Oct. 10, 1918 597,560 France Sept. 5, 1925 671,192France Aug. 31, 1929

